lampeodeema.] STEM0NITACEJ3. 125 SPECIES EXCLUDED FROM THE GENUS. E. muscorum L6v. = Lamiproderma irideum Mass. Genus 18.—LAMPRODERMA Rostafinski, Versuch, p. 7 (1873). Sporangia stalked," globose or ellipsoid; sporangium-wall membranous, somewhat persistent, shining with iridescent colours ; stalk black; columella cylindrical or clavate, reaching to half or more than half the height of the sporangium; capiUitium con¬ sisting of branched anastomosing threads, radiating from the upper part of the columella. KEY TO THE SPECIES OF LAMPRODERMA. A. Total height 2 to 3 mm. CapUUtium purplish throughout, spores spinulose, 10 to 13 /a. 1. L.. physaroides CapUlitium black or grey, spores echinulate, 15 to 20 fi. 2. L. echinulatum B. Total height 1 to 1-5 mm. a. Columella branching at the apex. 3. L. arcyrionema b. Columella obtuse or truncate. Threads of capilUtium dark, pale at the base. 4. L. irideum Threads of capilUtium dark or pale, not paler at the base. 5. L. violaceum 1. L. physaroides Rost., Mon., p. 202 (1875), and App., p. 25. Plasmodium? Total height 2 to 3 mm. Sporangia globose or ellipsoid, stipitate, erect, rarely sessile, gregarious, 0'5 to 0-8 mm. diam., purplish-black with broken iridescent reflections, or shining like burnished brass; sporangium-waU membranous, persistent, purplish in the lower part, usually mottled with darker shades. Stalk cylindrical, usually 1'5 mm. high, 0-15 mm. thick, purplish- black, shining, longitudinally striate or rugose, rising from a dark purplish hypothaUus. Columella cylindrical with a conical apex, or clavate, reaching to more than half the height of the spor¬ angium. CapUlitium of purple-brown threads, rarely pale, radiating chiefly from the upper part of the columella, sparingly forked and anastomosing; towards the surface branching and forming a deUcate, nearly colourless network. Spores purple- grey, closely spinulose, 11 to 14 /a diam.—Cooke, Myx. Brit., p. 49 ; Blytt, Bidr. K, Norg., Sop. iu. (1892), p. 7; Mass,, Mon., p. 103. Stemonitis physaroides Alb. & Schw., Consp. Fung., p. 103 (1805). Physarum columbinum PerS., Obs. Mye, i., p. 5. Lamproderma columbinum Rost,, Versuch, p. 7 ; in Fuckel, Symb., Nachtr, p. 69 ; Mon., p. 203 ; Mass., Mon., p. 100. Physarum iridescens Berk., in Hook. Journ. (1851), p. 20. Lamiproderma iridescens Rost., Mon., App., p. 25.